Bearing in mind the increasingly strict statutory regulations on the exhaust emissions of internal combustion engines and because of, at the same time, increasing customer demands with regard to a high driving comfort, internal combustion engines in motor vehicles must be controlled increasingly accurately. Sensors, such as for example temperature sensors, speed sensors, mass air flow sensors or pressure sensors measure the physical operating variables of internal combustion engines, which are processed by a control device. The control device, depending on the measured or derived operating variables of the internal combustion engines by activating different actuators, which for example adjust the throttle valve, the ignition point or the amount of fuel injected, can influence the operating behavior of the internal combustion engine. Above all, the engine torque generated by the internal combustion engine is controlled. Depending on the operating condition of the internal combustion engine, for example, during the starting phase and the warm-up phase, at idling or when accelerating, and depending on the activated comfort functions, such as for example, an air conditioner; different requirements are imposed on the engine torque to be delivered by the internal combustion engine.
A method for determining a target torque at the clutch of a motor vehicle is known from DE 196 12 455 A1. A minimum torque and a maximum torque are determined depending on a loss torque. Depending on a pedal value, the value depending on the angle of an accelerator pedal, on an engine speed and a correcting value of a driving speed regulator, a torque factor is determined. A target torque is determined by using the torque factor from the torque range given by the minimum and the maximum torque, the torque range depending on a loss torque. This target torque is corrected depending on derivative action torques, for example, the idle speed control, a function for heating the catalytic converter or for delimiting bucking vibrations and the loss torque. An actuating signal for a throttle valve actuator is determined as the output variable.
The target torque can be determined even more accurately, the more accurately the individual loss-torque fractions can be determined in each case. It has now been proven that in internal combustion engines with a fuel-supply device which has a high-pressure pump with a control valve for a volumetric flow, the loss torque determined is inaccurate.